1. Field of the Invention
The present invention relates generally to an aerosol sampler, and more particularly, to a multi-filter sampler for collecting PM 10 and PM 2.5 samples simultaneously.
2. Description of the Related Art
U.S. Patent Application No. 2010/0089183 disclosed a multi-filter sampler, which classifies particles by means of an impaction separator. Coarse particles with the aerodynamic diameter of 2.5-10 μm are led to pass through a first separation assembly and are collected by a 102 mm filter paper and three 47 mm filter papers, while fine particles having an aerodynamic diameter smaller than 2.5 μm pass through a second separation assembly and are collected by an 8×10 inch filter and four 47 mm filters. The user is consequently able to obtain the ambient air quality information by analyzing the filters. However, the filter cassettes have different flow rates from one another, so it is inconvenient to calibrate or operate the sampler, which results in inaccurate sampling.